The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
As this is known per se, an aircraft engine, which is generally of the turbine engine type, is placed inside a nacelle which, among other functions:                ensures aerodynamic fairing of the engine,        allows channeling of the outside air towards the engine,        allows the engine to be connected to the aircraft.        
Conventionally, the connection of the engine to the aircraft is made by means of a supporting structure comprising two upper longitudinal beams, conventionally called 12 o'clock beams because of their position at the top of the nacelle, two lower longitudinal beams, conventionally called 6 o'clock beams because of their position in the lower portion of the nacelle, and an assembly having a substantially annular shape called a front frame, in reality formed with two front half-frames each extending between said upper and longitudinal beams, and intended to be attached to the periphery of the downstream edge of the fan case of the engine.
Such a standard configuration is visible in FIG. 1 appended herein, wherein a rear nacelle portion has been illustrated, incorporating in this case a thrust reverser, this rear portion comprising,                two 12 o'clock beams 1a, 1b,         two front half-frames 3a, 3b respectively connected to 12 o'clock beams 1a, 1b and supporting deflecting grids 5a, 5b,         two half-cowls 7a, 7b each slideably mounted on a 12 o'clock beam 1a, 1b respectively so as to be able to expose the deflection grids 5a, 5b with view to achieving thrust reversal (6 o'clock beams not being visible in FIG. 1).        
As this is known per se, during thrust reversal, the air A1 from the fan (not shown) and circulating inside the secondary flow vein 9, flows through the grids 5a, 5b and is discharged towards the front of the nacelle, as indicated by the arrow A2.
The left 12 o'clock beam 1a and its associated left front half-frame 3a are illustrated individually in FIG. 2 in the assembled condition, and in FIG. 3 just before their assembly.
As this may be seen in FIG. 3, this assembly is conventionally made by providing an extension 11 on the beam 1b, which will fit inside a cavity 13 with a matching shape defined by the wall 15 of the front half-frame 3b. 
Once this fitting is achieved, rivets 17 will be attached in order to secure the extension 11 of the beam 1a with the wall 15 of the front half-frame 3b (see FIG. 4).
Such an assembling method is not entirely satisfactory, on the one hand because it only allows transmission of the forces on a portion of its section and on the other hand because the rivets are blindly mounted (i.e. they are only accessible from the outside), which makes their mounting and their inspection complicated.
Such an assembly also requires a very long shimming and therefore costly operation (machining of sometimes beveled shims).